She was one of Washington’s favorite “expert” yakkers, a familiar face and voice on internet and television panels, an authority on Korea, North and South, and a friendly interlocutor in interviews and casual conversation.

Now Sue Mi Terry is free on a $500,000 bond, accused of having sold much of her expertise, and done much of her talking, on behalf of South Korea’s multi-tentacle National Intelligence Service in return for designer coats and handbags and thousands of dollars in cash.

The news comes as a shock to those who had met her at think tanks and conferences. Always pleasant, glad to chat, she did not give the impression of a spy or double-dealer working both sides of the fence.  She seemed like what she had been years earlier —  a level-headed analyst at the CIA.

When I last encountered her, at a conference in Seoul in May, she briefed a small group on some of her impressions about North Korea — nothing sensational, just factual and some speculation about the future of leader Kim Jong-un.

Formerly with the Central Intelligence Agency, the National Security Council, and the National Intelligence Council, Ms. Terry not only failed to register as a foreign agent under the Foreign Agents’ Registration Act, according to the indictment handed up by a grand jury in Manhattan, but also conspired to get others to do the same. Each charge carries a maximum sentence of five years in prison.

Always personable, willing to discuss views in between sessions at a conference, she was most expressive on a show called “Capital Cable” put on at the Center for Strategic and International Studies in Washington. She and the CSIS star on Korean issues, Victor Cha,  would hold forth while a former American ambassador to Korea, Mark Lippert, asked questions.

The indictment, signed by the United States Attorney for the Southern District of New York, Damian Williams, alleges that Ms. Terry “subverted foreign agent registration laws in order to provide South Korean intelligence officers with access, information, and advocacy.” Mr. Williams adds that “the charges brought should send a clear message to those in public policy who may be tempted to sell their expertise to a foreign government to think twice and ensure you are in accordance with the law.”

Ms. Terry’s attorney, Lee Wolosky, made clear she would fight the charges. “These allegations are unfounded and distort the work of a scholar and news analyst known for her independence and years of service to the United States,” he declared. “Once the facts are made clear it will be evident the government made a significant mistake.”

Born in South Korea, Ms. Terry, 54, arrived at age 12 in America with her mother after the death of her father. She went to New York University and earned a doctorate at Tufts University, then went to the CIA as an analyst on North Korea and, later, on Korea and Japan at the National Security Council during the George W. Bush and Obama presidencies.

Leaving government, Ms. Terry became a presence at CSIS, then the Wilson Center in Washington, and most recently as Korea expert at the Council on Foreign Relations, which has placed her on unpaid leave.

It was after Ms. Terry entered the think tank world that she bonded with the Korean embassy in Washington, according to the indictment, providing information, advice and introductions — and even writing commentaries saying what Korea’s National Intelligence Service wanted out there.

Her “handlers gifted her, among other things, a $2,845 Dolce & Gabbana coat, a $2,950 Bottega Veneta handbag, and a $3,450 Louis Vuiton handbag,” the indictment goes on to say. Besides taking her to upscale restaurants, it says, “they also offered to provide $37,000, worked with her to devise a plan to mask the true source of those funds and deposited the funds into an unrestricted ‘gift’ account that Terry controlled at the think tank where she worked.”

The indictment alleges that the South Koreans had Ms. Terry write an opinion piece, “South Korea Takes a Brave Step Toward Reconciliation With Japan,” on President Yoon coming to terms with Japan’s prime minister, Fumio Kishida. The Washington Post ran the commentary on March 7 of last year under the bylines of Ms. Terry and columnist Max Boot, who is Ms. Terry’s husband.